Overhead work, such as wiring, ductwork, painting, etc. often requires the assemblage of scaffolding towers to provide a platform for a worker or workers. Once assembled, these scaffold towers are often difficult to move from place to place, requiring either a worker dismounts the scaffold and pushes it himself, or that another worker be stationed below for this scaffold moving job.
In contrast this power unit for attachment to scaffolding assemblies allows a worker to remain aloft on the scaffolding, while controlling the movement of the scaffold assembly about the worksite. This scaffolding power unit is easily attached and easily removed from a scaffold assembly. At least two other castering wheels of a scaffolding subassembly are kept from pivoting, by a removable locking subassembly quickly installed on each castering wheel, to increase the steering effectiveness of this power unit. If the power units are used in tandem, to provide increased maneuverability, the locking subassemblies are unnecessary.
Past power units for scaffolding towers, which have been attached to the rear portions of scaffolding framework and have a front steering wheel are disclosed in U.S. Pat. Nos. 3,256,954, and 3,232,375. In U.S. Pat. No. 3,520,382 is a hand driven scaffold. In U.S. Pat. No. 3,930,548 two drive units are disclosed with a stabilizing bar connected between them. The prior motorized attachments for scaffolding towers are often more difficult and time consuming to attach; are often of limited traction due to their mounting methods; often require a special type of scaffolding tower, thereby limiting their versatility; and also often obstruct the area between the legs of the scaffolding such that building materials and other possible items cannot be passed between the scaffolding legs, consequently making the scaffolding tower assembly more difficult to move about to new positions.